Catalogue raisonné rejects unusual part-painting, part-sketch, as expert says the “colonial” nature of the composition is not the artist’s style

French expert Marc Restellini claims substantial modifications to Italian painter's 1915 portrait of Beatrice Hastings were not mentioned by Christie's when the picture was sold—twice

Institute is claiming copyright ownership and right to publish expert’s research, alongside share of profits from Institut Restellini which it claims charges €30,000 per inquiry